Half to william



( No Model.) 3 SheetsSheet.1. J. B. PIT'OHPORD.

GUT-OFF VALVE GEAR..

Patented Jan. 6,1885. v

(No Model. 3 Sheets-Sheet 2.

Jr B. PITOHPORD.

GUT-OPP VALVE GEAR.

No. 310,310. Patented Jan. 6, 1885.

3 SheetsSheet 3.

(No Model.)

J. B. PITOHPORD.

GI IT-OFFVALVE GEAR.

Patented Jan. 6,1885;

35 to that shown in Fig.1.

45 C the piston-rod.

UNITED STATES PATENT. OFFICE.

JOHN B. PITCHFOBD, OF SAN FRANCISCO, CALIFORNIA, ASSIGNOR OF ONE- HALF TC XVILLIAM T. G-ARRAT'IXOF SAME PLACE.

CUT- OFFVALVE GEAR.

SPECIFICATION forming part of Letters Patent No. 310,310, dated January 6,1885.

Application filed April M. NH. (No model.)

To aZJ whom, it may concern.-

Be it known that I, J oIrN B. Pironronn, ol' the city and county of San Francisco, and State of California, have invented an Improvement in Cut-Off-Yalve-Gear; and I-hereby declare the following to be a full, clear. and evact description thereof.

My invention relates to a mechanism by which steam may be cut off after the valve has been opened to admit it to an engine-cylinder, and the speed of the engine regulated to suit the work to be done.

It consists of an equalizing arm or lever which is so connected with the valve-stem of [5 an engine that movement can beimparted to the valve from two different sources at the same or at different ti mes, as may be required, for the purpose of opening and closing the valves and admitting and cutting off steam to suit the load of the engine.

Referring to the accompanying drawings for a more complete explanation of my invention, Figure 1, Sheet 1, is a side elevation, showing the application of my invention to a reversibleenginewith rotary oscillating valves.

Fig. 2 is a longitudinal section of the steamcylinder, steam and exhaust chambers, and a transverse section of the valves. Fig. 3 is a view of the regulating mechanism or governor.

0 Fig. 4. is a section of the cam and gear, taken through the plane of the axis of the shaft, showing also the forward and back eccentrics. Fig. 5 is a View of the equalizing-lever and a valve rocker-arm. Fig. 6 is the opposite cam Fig. 7 Sheet 2, shows the application of the equalizing-levers to a Corliss engine. Fig. 8, Sheet 3, is a view showing the lever operated by an eccentric with an adjustable throw. Fig.9 is a plan view of 0 the mechanism, showing the stationary and the adjustable eccentric. Figs. 10 and 11 show the manner of attaching the movable eccentric, and the slot allowing its adjustment.

A is an engine-cylinder, B the piston, and D is the steam-chest, with the inlet D, and E is the exhaust-chamber, with discharge at F. The valves G extend transversely through chambers H, so formed at each end between the steam and exhaust 5o chambers that the valves by their oscillation may open communication from the steamchamber to the cylinder through the port 1 and passage J, and when turned to the proper point will open communication between the cylinder and the exhaust-chamber by means of the curved passage K, formed upon one side of the valve. The valves are oscillated by l 0(ikl tl'lll$ L, lived to stems projecting through stuffing-boxes in the ends of the valvechambers.

M is an equalizing-lever, the center of which is suspended upon the pin at the outer end of the rocker-arm. The ends of this lever have pins, to which rods N N are attached. The rods N connect with the block 0, which is actuated by eccentrics through the link P,.

thus giving a regular movement and ameans for reversing in the usual manner. The rods N connect with links Q, and these are actnated by eam-grooves R it. are of such shape that during the first part of the stroke of the engine they simply hold the end of the lever M, with which they are connected, while the eccentric moves the other end, and thus opens the valve. At the point where it is desired to cut off the steam from the engine the cam-groove actsto draw the end of the lever with which it is connected backnntil the valve is closed.

In order to adjust the point of cutting off to regulate the speed of the engine, the camgrooves, which are formed on opposite sides of a disk, have a gear, S, formed on the hub a little to one side. The cam-grooves and gear, being made in a single piece, are bored, so as to turn loosely upon the engine-shaft, as shown in Fig. 4. Curved arms T have their outer ends pivoted to a disk,U, and their inner ends are toothed, the teeth engagingthose of the gear, asshown in Fig. 3. These arms have weights V upon them, which draw them it outward by centrifugal action when the engine runs fast, and thus turn the gear and the cam-grooves in a direction which causes them to act to close thevalves sooner; but when the engine runs slowly springs W act to draw the arms inward and turn the cam-grooves in an opposite direction, so that they will act later and leave the valve open longer. In the present case I have shown the two cam-groovesone for each end of the cylinder-cut in opposite sides of a disk, the hub of which has the Thesecaiu-grooves 7 gear out upon or fixed to it, as before described. Short sliding bars X move in a guide-block, Z, and have pins which enter the cam-grooves It R',by which they are moved. Their opposite ends are connected with the links Q by rods a.

I do not particularly claim or limit myself to the means for adjusting the cams which I have here described, as governors have been constructed in a similar manner, and other devices may be applied to my gear which will adjust or regulate it equally well.

Fig. 6 shows the application of my device to a Corliss engine in which two steam-valves and two exhaust-valves are operated from a central disk, b,which is actuated by an eccentric upon the main engine-shaft in the usual. manner. In this case one end of the lever is connected with the disk and the other with cam-grooves on the engine-shaft, similarly to those before described.

In-Sheet 3, Figs. 8 to 11, I have shown an eccentric slotted so as to'be moved upon the shaft by the centrifugal action of the weighted arms, and thus increase or diminish its throw. In this case the main fixed eccentric c is connected with one end of the equalizing-leverand the adj ustable eccentric (Z is connected with the opposite end of the lever. The act-ion of this eccentric as its throw is lengthened or shortened will be to increase or diminish the move ment of the valve.

The invention is specially applicable to the independent double-ported stezmrvalves of the Corliss type. as the movement requi red is much less than with a slide-val ve,an d the cutoff can take place on one valve at any time without affecting the valve at the other end of the cylinder. \Vhcn used with a single slide-valve, it is less effective, for the reason that it requires too great a travel of the valve, and consequently a large movement of the cam, and there is also a tendency to choke the exhaust passage.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. In an engine valve-gear, an equalizing arm or lever which is connected with the val vestem of the engine, a mechanism, substantially as described, by which movement may be imparted to the valve through it from two different sources at the same time or at different times, and mechanism, substantially as described, for automatically varying the cut-off point of the valve.

2. In an engine, a single rotary steam and exhaust valve for each end of the cylinder, rocker arms fixed to the valve-stems, and equalizing-levers M, with their centers journaled on pins on the rocker-arms, together with cam-grooves 011 the main engine-shaft, connected with opposite ends of the equalizinglevers, substantially as herein described.

3. In an engine,the single rotary steam and exhaust valves for each end of the cylinder, with rocker-arms and equalizing-levers, fixed eccentrics connected with one end of the equalizing levers, and adjustable eutoff camgrooves connected with the opposite ends of the levers, substantially as herein described.

4. In an engine, single rotary steam and exhaust valves at each end of the cylinders, with rocker-arms and equalizing-levers, fixed eccentrics connected with one end of the equalizing levers,with intermediatereversing-links,

and adjustable cut-elf canrgrooves connected v with, the other ends of the levers, with inter-- posed links by which the cut-cit gear may be reversed or thrown out of action, substantially as herein described.

5. In combination with the rotary valve of an engine, an equalizing arm or lever connect ed with the pin on the rocker-arm of the rotary valv e at a point between the ends of said arm or lever, an eccentric, and connection between said eccentric and one end of said lever, a grooved cam and connection between it and the other end of said arm or lever,and a governor connected with and controlling said grooved cam, all substantially as described.

In witness whereof I have hereunto set my hand.

J. l3. PITCHFORD.

\Vitnesses: O. D. COLE, E. A. BRANDAM. 

